Electric power-transmission system.



I. R. MARKLE.

ELECTRIC POWER TRANSMISSION SYSTEM.

APPLICATION FILED MAY 13. 1911.

4 SHEETSSHEET I.

ZE- ven%7 jZn/aiharlze.

J. R. MARKLE.

ELECTRIC POWER TRANSMISSION SYSTEM.

APPLICATION FILED MAY l3 19!].

1,139,882. Patented May 18, 1915.

4 SHEETS-SHEET 2- J. R. MARKLE.

ELECTRIC POWER TRANSMISSION SYSTEM.

APPLICATION FILED MAY 13, 1911.

1,139,882. Patented May 18, 1915.

4 SHEETS-SHEET 3- 1, R. MARKLE.

ELECTRIC POWER TRANSMISSION SYSTEM.

APPLICATION FILED MAY I3, 191!- 1,139,882. 7 Patented May18,1915.

4 SHEETSSHEET 4.

JOHII R. MABKLE, OF CHICAGO, ILLINOIS.

ELECTRIC POWER-TRANSMISSION SYSTEM.

Application filed May 18, 1911.

To all whom it may concern Be it known that I, JOHN R. MARKLE, a

' citizen of the United States, residing at Chicago, in the. county ofCook and State of Illinois, have invented new and useful Improvements inElectric Power-Transmission Systems, of which the following is a full,clear, concise, and exact description, reference being had to theaccompanying drawing, forming a part of this specification.

My invention relates to a system of elec trieal power transmission,particularly adapted to conveyances, such as automobiles, marine craft,railway cars, and the like, although some of the features thereof may beused in other connections and for other purposes. By my invention I amable to produce a system for the electrical translation, transmissionand distribution of power which possesses important advantages,hereinafter set forth, over the systems of the prior art.

It is one of the objects of my invention to provide an eflicient andsimple electrical. power transmission system which may be interposedbetween a prime mover mounted on the conveyance and the propellingmeans, and in the use of which variation of speed and reversal ofdirection'of movement may be accomplished without the use of clutchmechanism or mechanical reversing gear. By my electrical powertransmission system the operator can start, stop or reverse thedirection of movement of the conveyance by electrical means of controland can vary the speed by either mechanical or electrical means, orboth, as may be preferred.

A further object of my invention is to provide effective means for thetransmission of power from a suitable prime mover to a driven part withinterposed electrical transmission means and suitably associatedregulating means," whereby the starting and stopping and direction ofrotation of the driven part, as well as the speed and the torquethereof, may be varied at the will of the operator.

Other objects of my invention will hereinafter more fully be set forth.-

For the purpose of disclosing my invenv tion I have illustrated certain"embodiments thereof in the accompanying drawings. It

' Specification. of Letters Patent.

Patented May 18, 1915.

Serial No. 626,971.

will be understood that these drawings illustrate a few only of theembodiments of which my invention is capable.

Figure 1 is a simplified diagrammatic view of the system of my inventionshowing the same in connection with a constant speed adapted thereto thesystem diagrammati-' cally illustrated in Fig. 4; Fig. 6 is a bottomplan view of the automobile illustrated in Fig. 5; Fig. 7 shows myinvention applied to the operation of a plurality of driven parts, as ina train of cars or the like; Fig. 8 shows my invention applied to aparallel plan of cross connection.

Referring to Fig. 1, which illustrates diagrammatically in simple formone of the embodiments of which my invention is capable, let 10 indicatethe prime mover, which may consist of a gasolene, steam, or othersuitable form of engine and which in the arrangement shown may be anengine of the constant speed type having a suitable governor formaintaining the speed constant. 11 indicates a generator armaturesuitably connected to and driven by the engine, and 12 a motor armaturewhich is supplied with energy from the generator armature 11. Thearmature of the motor 12 is connected across the armature of thegenerator by conductors 13, 13 and in the circuit thus formed isinterposed circuit controlling and reversing means which may take theform of a switch 14, which for convenience of illustration is shown asan ordinary double throw reversing switch, but which may be a drumswitch or of any other preferred form. This switch is designed to whichare connected across the generator armature, and the circuitthus formedmay, as in the particular embodiment illustrated in this figure, alsoinclude the field winding 17 of the generator. and satisfactory resultsin practice, the field windings of the generator and the motor 1 varyingthe speed of the motor. -As shown in the arrangement illustrated in Fig.1, the speed controlling means may take the form of a field rheostat 18interposed in the circuit including the field windings of thegenerator'and the motor, which circuit may for convenience be termed themainfield circuit. This main field circuit constitutes an individualcircuit which may be traced from the positive brush of the generator,through the field winding 17 of the generator, conconstant speedengines.

ductor16, rheostat 18, field winding 15 of the motor,- and the otherconductor l6 to the negative brush of the generator. As clearly appearsfrom the drawings, the

' motor armature on the one hand and the field windings of the motor andthe generator on the other'are in individual circuits, and it thereforeresults that the field of the motor may be continuously excited so longas the prime mover is in operation, irrespective of the condition of thearmature circuit of the motor, Whether open or closed, and whethercurrent through the armature flows in one direction or the other. Thisfeature of having the field winding of the motor in an individualcircuit which is separate from and independent of the armature circuitof the motor and which may be continuously-excited during the running ofthe prime mover, whether the armature circuit is open or closed, isproductive of important practical results. Owing to the continuousexcitation of the motor field and the consequent continuous field offorce which results, the armature circuit may, if

desired, be closed by means ofa'n ordinary switch l'to admit current tothe motor armature without the interposition of the commonly employedstarting or regulating resistance.

In starting the apparatus the engine 10 will be started and brought tothe required speed and will be maintained at that speed through theagency of the usual automatic governing device commonly employed withThe resistance of the field-rheostat will, at starting, be all includedin circuit, so that as the armature of the generator rotates it willmove in a weak field of force. In consequence, the current generated inthe generator armature will be For the most efiicient correspondinglysmall. motor armature circuit may therefore be closed to admit currentto the motor armature. The field of the motor will be correspondinglyweak. As the arm of the field rheostat is movedto cut out the resistancestep by step, the field of the generator, as well as the field of themotor, will be gradually built up together and the speed of the motorarmature and the torque exerted thereby will correspondingly increase.The motor armature may thus be brought gradually to full speed. Bymanipulating the arm or controlling handle of the field rheostat thespeed of rotation of the motor armature may be varied at will during thenormal operation thereof. The motor armature may be brought to rest atwill without stopping the engine by opening the switch in the armaturecircuit and may be started again by closing the switch, and thecurrentthrough the motor armature may be reversed through the agency ofthe switch to cause such armature to rotate in the opposite direction.If desired, the arm of the rheostat may be provided with a spring, asindicated in dotted lines in Fig. 1, so that when the arm is released bythe operator it will be automatically returned to its initial positionand thereby reinsert the resistance in the field circuit, thus weakeningthe field and acting as a throttle valve to the system.

In accordance with my invention, 1 may dispense with the starting orregulating rheostat commonly employed with electric motors. By linkingthe armatures and field windings together as described, thegenerator-motor system becomes a unit in which the several interrelatedelectromagnetic elements co-act to permit the starting and stopping andreversal of the motor armature under full or partial load bymanipulating the simple circuit opening and reversing switch. Theopening of the motor armature circuit leaves the motor field energizedin readiness for the quick re-starting of the motor armature upon there-closing of the motor armature circuit, and this re-starting may beaccomplished without the employment of any protective armatureresistance, such as has heretofore been usually em-' ploved in practice.

Preferred results are secured by having both the generator field and themotor field inthe same circuit. By moving the rheostat lever to increasethe resistance in the main field circuit the field of the generator willbe weakened and the electromotive force developed by the generatorcorrespondingly decreased, thereby developing less torque and decreasingthe speed of the motor. If suflicient resistance is inserted in the mainfield circuit the point will be reached where the torque of the motorwill be so reduced in view of the load that the motor will be The switchin the v brought to rest. Conversely, when the resistance in the mainfield circuit is decreased, the field of the generator will bestrengthened and a higher electromotive force will be developed by thegenerator, the increased power of the generator acting directly upon thearmature of the motor to cause the same to develop greater torque andincrease in speed.

By placing the generator and motor field windings in the same circuit,one field rheostat may serve for both fields, and, moreover, thebuilding up of the two fields uniformly and in unison is insured. Lesscurrent is requiredto energize the fields and in consequence the fieldsbuild up more rapidly. Owing to the inclusion in the main field circuitof the two field windings in series, the field strength is such that themotor armature accelerates quickly, permitting a quicker and saferstarting 'of the motor armature under load. Should the circuit of themotor field winding be broken or opened through accident. a dangerousflow of current through the motor armature is prevented. because thecircuit through the generator field winding wculd likewise be open andthe generator field dead, so that the generator could not generatecurrent, and consequent danger of motor armature burn-out is eliminated.By placing the -provided with any suitable or ordinary fields of thegenerator and motor or motors in series the difference of potentialacross each field is reducedand the liability of breaking down the fieldinsulation or of burn-outs is consequently reduced.

Instead of employing a constant speed engine and an electricalcontroller, as in the arrangement shown in Fig. 1, I may employ as theprime mover for driving the generator an engine having means for varyingthe speed thereof, so that by varying the speed of such engine, thespeed of the generator and motor may be correspondingly varied. Such anarrangement is diagrammatically illustrated in Fig. 2. In thismodification the armature circuit and independent main field circuit aredesignated 13, 18, and 16, 16, respectively. In this instance the fieldrheostat shown in Fig. 1 is omitted, while the prime mover 10 is means,such as a throttle 19, for varying or regulating the speed thereof. Asin the arrangement shown in Fig. 1, the motor field winding may becontinuously excited while the prime mover is'in operation and the motormay be started, stopped or reversed by movement of the switch 14 in thesame manner as described in connection with Fig. 1 and without affectingthe conor torque regulation of the motor is attained by movement of thethrottle valve to increase or decrease the speed of the prime mover orvengine. As the speed of the generator will vary as the speed of theenginevaries, the power output of the generator will likewise vary, andas the energy to drive the motor is supplied by the generator, it isobvious that by merely increasing or decreasing the speed of the primemover the speed or torque of the motor may be varied at will.

In starting, the switch 14 may be closed to connect the motor armaturein circuit with the generator armature, and then, by means of thethrottle, the engine may be gradually started to bring the motorarmature to full speed, or such other speed as may be desired. The motorarmature may thus be gradually started under normal load without unduestrain upon the system. The motor armature may be stopped, if desired,without stopping the engine, by opening the armature switch 14 and maybe started again by closing the switch; or, if desired, the direction ofrotation of the motor armature may be reversed without stopping theengine by reversing the armature current through the agency of thearmature switch 14. If desired, the motor armature may be stopped bystopping the engine or may be up more rapidly than would be the casewere they in separate circuits. T he motor armature is thus set inmotion and brought to speed under load in the least possible space oftime and without the flow of inj urious current through the motorarmature.

In Fig. 1 I have shown a field rheostat in the main field circuit forvarying the speed or torque of the motor, the prime mover being 'of theconstant speed type, while in Fig. 2 such speed and torque variation isbrought about by employing a variable speed prime mover. If desired,however, and while still retaining the advantages of my invention, bothof these means may be employed for regulating the speed and torque ofthe motor. Such an arrangement is diagrammatically depicted in Fig. 3.In this modification the prime mover which drives the generator consistsof the engine 10, having means, such as the throttle 19, for varying thespeed of the same, as in the arrangement shown in Fig. 2. interposed inthe main field circuit 16, as in Fig. l, is a field rheostat 18. \Viththis arrangement the speed of the motor may be varied by manipulatingthe rheostat, as pointed out in connection with F 1, or by varying thespeed of the prime mover, as described in connection with Fig. 2. Or, ifdesired, the speed and torque of the motor may be varied by the conjointmanipulation of the mechanical and electrical controllers.

In the various modifications heretofore described, irrespective of themeans employed for controlling the action of the motor, the armature ot'the motor is in one independent circuit supplied with current at varyingvoltage from the armature of the generator while the field of the motoris in another independent circuit supplied with current from thearmature of the generator. Moreover, the field of the motor isenergized, so long as the prime mover continues in operation,independently of the current through the armature of the motor, so thatthe armature circuit may be opened, closed or reversed withoutobjectionably aifecting the field excitation of the motor. Vith thisarrangement the current may, as before stated, be admitted to the motorarmature without the interposition of any protective starting orregulating resistance. In other words, with my invention rheostaticregulating devices in the armature circuit may be dispensed with and asimple circuit closing or reversing switch may be employed in thearmature circuit, so that current through the armature can be out 01f tostop the motor or admitted to start the motor, and so that the directionof the current through the armature may be reversed at will to alter thedirection of rotation of the motor armature.

In the embodiments of the invention illus trated in Figs. '1, 2 and 3,the only field windings shown are those included in what I have termedthe main field circuit. The invention may, however, be embodied inconnection with various forms of generators and motors which may besupplied with field windings otherwise connected in circuit and eithercompounded with respect to the mainfields or otherwise. For example, thearrangement may be as illustrated in Fig. 4, which in practice has beenfound to give ideal results. In this instance the generator 20 and motor21 are illustrated as of the four pole type, and are provided withcommutating poles. For convenience of illustration, the prime mover orengine is omitted, although it is to be understood that the generator 20is driven by suitable power, as heretofore explained in connection withFigs. 1, 2 and 3.

The main field circuit 22, which corresponds with the circuit 16, inFigs. 1, 2 and 3, may be traced from the positive brush of thegenerator, through the main field windings 23 of the generator, thenceto the motor, through the main field windings 2t of the motor and thento the negative brush of the generator. This main field circuit may haveincluded therein a field rheostat, as in the arrangement shown in Fig.1, but in the present instance is not provided with such rheostat. Inany event, the main field cir cuit of the motor, as in the arrangementspreviously described, is an independent circuit by means of which thefields 24: of the motor, and in the present instance the fields I 23 ofthe genera tor, are continuously excited during the operation of theprime mover independently of the motor armature.

The armature circuit of the motor, which in the embodiment of theinvention illustrated in Fig. 4 also includes the compound windings ofthe generator and motor as well as the commutating pole windings of bothmachines, may be traced from the positive brush of the generator throughthe commutating pole windings 25 of the generator, then through theseries fields 26 of the generator, then by conductor 27 to and throughthe series fields 28 of the motor, then by conductor 29 to the armaturereversing switch 30. With the reversing switch in the positionillustrated in the drawings, the circuit continues by way of conductor31 to and through the armature of the motor, then through the windingsof the commutatingpoles 32 of the motor to conductor 33 back to thereversing switch 30, and by way of conductor 34 to the negative brush ofthe generator. With the reversing switch in the position illustrated,the conductors 29 and 33 are connected by suitable contacts with theconductors 31 and 34 respectively. \Vhen the switch is in its otherextreme position, the conductor 29 is, by means of suitable backconnections, connected to the conductor 33 whilethe conductor -31 isconnected to the conductor 34, thereby reversing the -direction ofcurrent through the a motor armature. In the neutral position of theswitch the armature circuit is opened. As the switch 30 is located inthe armature circuit between the field windings 28 and the motorarmature, the reversal of the armature connections does not affect thedirection of the current through the fields 28. It will be observed,however, that the commutating pole windings of the motor are connectedin circuit between the armature and the reversing switch so that whenthe armature current is reversed the current through these windings willlikewise be reversed, as is required when such commutating poles areemployed.

As in the'embodiments of the invention illustrated in Figs. 1, 2 and 3,the main field windings of the motor in Fig. 4 are concd mereiy for purnected to the armature of the generator through the agency of a circuitwhich is independent of the circuit which supplies current to thearmature of the motor, so that the opening of the armature circuit tostop the motor or the reversal of the leads to change the direction ofrotation will not ali'ect the excitation of the motor field magnetssufiicient for starting, re-starting and reversal purposes. Inconsequence, as is the case with other arrangements which embody theinvention, the fields of the motor are continuously excited, wholly orin part, and when current is admitted to the motor armature, thearmature quickly speeds up and a protective c0 nter-electromotive forceis developed.

In Figs. 5 and 6 I have shown my inventlon (specifically the embodimentof the inwntion illustrated in Fig. 4) as applied to an .UlLOillOblle.While a conveyance of this tvpe in used for purposes of illustration, its to be understood that this is not intended as a limitation, theautomobile being selectoscs of convenience in showing theildilplizttiiiil of the invention to a conveyance, the electrical powertransmission system being equally adapted for use with marine craft,cars, railway trains, trucks, traction engines, elevators, hoists, andother forms of conveyance, and to some extent in connection withtransmission systems generally. as heretofore indicated. 'ith thisunderstanding. and referring to Figs. 5 and (3, the numeral 85 indicatesan ordinary automobile provided with the usual drive shaft 36,transmission gear 37, driving wheels 38 and steering wheel 39. Mountedin or on the conveyance is the prime mover, vhich in the presentinstance is shown as a gasolenc engine i0, provided with suitable meansfor varying the speed thereof, as by means of the throttle e1, which, asis usual with automobiles, is controlled by a connection i2 extendingfrom the throttle to the hand lerer 4-3 on the steering wheel 39. Bymanipulating the lever 43 the speed of the engine maybe varied in theusual manner, or the speed of the engine may be controlled in any othersuitable manner. Also mounted in or on the conveyance is the electricalgenerator 20. shown in Fig' l, the armature shaft of which is connectedto the engine shaft in any suitable manner so that the generator will bedriven by the engine. In the illustration, the armature shaft of thegenerator is connected directly to the engine shaft so as to be drivenat the same speed as the engine. This is not material, however,

as any suitable connecting or power transmitting means may be employed.The motor 21 is mounted on the conveyance in a convenient position andhas its armature ronnectwl in any suitable way to the drive shaft 36,and the starting, stopping and reversing switch'30, which is preferablyof the drum type, is operated by means of a lever 4A convenientlylocated with respect to the driver and connected to the switch 30 byconnecting rod 45.

In the embodiment of the invention illustrated in Figs. 5 and (3, thespecific circuit arrangement of which is shown in Fig. i, the speed ofthe conveyance is controlled by varying the speed of the engine bythemechanical controller, while the starting, stopping and reversal ofdirection of the conveyance are controlled through the medium of theswitch or electrical controller 30. Owing to the fact that so long asthe prime mover is in operation the main field windings of the motor arecontinuously excited, the degree of excitation depending mereiy upon thespeed at which the e gine running. the driver or attendant .an startunder heavy load with adequate torque in the motor by closing thearmature circuit through the medium of the switch and then graduallystarting the engine; and he can reverse the direction of movement of theconveyance without stopping the engine merely by throwing the switch 30to reverse the motor armature connections. He may stop the vehiclewithout stopping the engine by opening the switch 30 and may restart byclosing the switch. Moreover, the starting and reversing may beaccomplished without the employment of the customary armature startingresistance and without danger to the motor, for the reasons explained.

By the use of my invention the speed may be controlled and theconveyance stopped and started at will without employing speed reducinggearing or clutches of any kind, while at the same time the operator ordriver has perfect control over the conveyance. A wide differencebetween engine speed and motor speed is obtainable by suitably windingthe generator and motor. Thus the generator may be designed to run at ahigh normal speed while the motor may be designed to run at a low normalspeed, or vice versa. The speed may be stepped up or stepped down fromthe generator, as may be desired, to meet the particular conditions athand. Any desired speed ratios between generator and motor are thuspossible. A. high speed engine may be coupled with a low speed drivenpart, or vice versa.

It will be obvious that in the use of my invention a single generatormay be coupled with a plurality of motors, as when the invention is usedin connection with a train of cars. Under such conditions, the motorsmaybe connected with the generator in any preferred manner, as by arr-aning the armatures of the motors in paraillel. across thegeneratorarmature whilevthe fields of the motors are, for example, --connected inseries in the main field circuit. Such an arrangement, which is merelyillustrative of one way of connecting a plural ity of motors with asingle generator in embodying my invention, is shown in Fig. 7, where 10indicates a variable speed engine, 11 the generator, and 12, 12 aplurality of motors, the armatures of the motors being connected inparallel across the armature of the generator while the fields of themotors are connected in series in the main field circuit. The primemover, generator, and starting, stopping and reversing switch wouldpreferably be located in the pilot car, and each car of the trainprovided with a motor connected to the driving gear thereof. With thisarrangement all of the motors can be controlled simultaneously for speedregulation as well as in starting, stopping or reversing.

The employment of a single generator with a plurality of motors, asdepicted in Fig. 7, may also be used with advantage for the propulsionof multiple propeller water conveyances, each propeller being driven byits own motor, although in large water craft it would be preferable tohave a separate engine and transmission system for each propeller sothat each propeller could be operated independently. It will also be obvious that a plurality of separate generator-motor units may be sointerrelated that it will be possible to connect any one of thegenerators with one or more of the motors,

or to connect all the generators with any one of the motors. Such anarrangement would be found desirable, for instance, in the propulsion ofwater craft, when, as above suggested, it was preferred to have aseparateengine and transmission system for each propeller. A suitablearrangement for such purpose is illustrated in Fig. 8, in which figureeach of the generator elements 11, 11 11, may be assumed to be driven byan associated prime mover, which for convenience of illustration is notshown, and adapted to supply current to a plurality of motor elements12*, 12, 12. In the particular circuit selected for purposes ofillustration, the generator element 11 and motor element 12 may beregarded as one unit, the generator element 11 and motor element 12anothercunit, and the generator element 11 and motor element 12 a thirdunit.

Suitable connection is made between each of the generators and'bus bars45, to which bus bars the armature and field winding circuits of themotors are likewise connected.

Interposed in the connections leading from.

each generator to the associated bus bars is a switch 46, while a switch47 is likewise interposed between each .motor and the bus bars. When theswitches are in the position illustrated in the drawing each generatoris connected to its own motor. If for any reason it is desired to driveall the motors from one generator, as, for example, the generator 11,the switches 46 of the generators 11' and 11 are opened, and theswitches 47 of the motors 12 and 12 are thrown to the extreme leftposition, thereby connecting the three motors to the bus bars, to whichthe connections leading from the generator 11 are connected, in thisinstance the 1st, 4th, 7th and 10th bus bars. The three motors will thenbe in parallel with the armature of each connected across the armatureof the generator and its field in series with the field of suchgenerator. Likewise, by suitable manipulation of the switches 46 and 47any generator may be connected to any one or all of the motors. If, forexample, the generator 11 or its prime mover should break down, thegenerator 11 may be connected to the motors 12 and 12 while thegenerator 11 continues to operate its associated motor 12. Various othercombinations of the generators may be effected by manipulating theswitches 46 and 47. In any such combinations the armature of each motorwould still be connected across the armature of the generator drivingthe same while its field winding would be connected in a circuitindependent of the armature circuit. In order to reverse the motors areversing switch 49 is connected in the armature circuit of each motorbetween the armature and the associated switch 47.

It is apparent from the foregoing description of various embodiments ofmy invention--which, of course, are a part only of the possibleembodimentsthat all the field windings of the motor need not be in thein dividual field circuit which is independent of the current suppliedto the motor armature. A part of the motor field windings may be inseries with the motor armature, as in Fig. 4, or a part may be otherwisedisposed where the same may or may not be partly or wholly dependentupon, or affected by, the motor armature current. But I contemplatehavin either all or at least a part of the motor eld winding suppliedwith current by means of an individual. circuit, so that the circuitthrough the motor armature may be opened, closed or reversed withoutaffecting the continuous excitation of the motor field to full extent orto such ex tent as may be necessary or desirable for practicablestarting, re-starting and reversing purposes, as heretofore explained.

It. will be noted that through the agency of my invention a starting orregulating resistance in the motor armature circuit may be dispensedwith. Such a starting or regulating resistance may, of course, beemployed if desired, but it is unnecessary and v of switching means inthearmature circuit,

mac-see may be wholly omitted. The only switching means employed in themotor armature circuit is the switch for opening and closin the circuitfor starting and stopping, an

preferably the reversal in the direction of rotation is accomplishedthrough the agency although the reversal in the direction of rotationmay be otherwise accomplished if preferred.

When, as in Fig. 2, the variation in speed is accomplished through theagency of a mechanical controller or throttle in connection withtheengine, rheostatic controlling devices of all kinds may be dispensedwith. When, as in Fig. l, a constant speed engine is employed, arheostatic controller may be desirable for controlling the fieldstrength, but even in this case no rheostatic controller a in thearmature circuit is necessary. By in cluding the field winding of thegenerator and the field winding of the motonin the same circuit, onefield controller is cient for the control of both fields.

The system of my invention isfinarkedly eficient. No rhcostaticresistaniceis used in the armature circuit, thereforethere are no deadlosses due to the same. All power units required can be operated atpractically maximum efiiciency for any given power re quired. Forexample, if only small power is required, it will not be necessary torun the engine and generator at a high speed, thereby includingunnecessary losses due to friction, windage, and inherent losses in thegenerator, but the complete engine-generator-motor unit (Fig. 2) can berun at such slow speed as may be required to give the power desired,with higher efiiciency and increased life. Any number of examples willsuggest themselves to those skilled in the art whereby by the use of myinvention the speed of the apparatus may be lowered for low power orraised for high power, as may be required.

The system of my invention afiords an extremely flexible method ofcontrol. Almost any reduction in speed from the engine to the motor andthereby to the driving shaft can be obtained, also an infinite num berof steps in speed can be secured by either changing the speed of theengine (Fig. 2) or by varying the field strength (Fig. 1), or throughthe agency of both these regulating means (Fig. 3), or otherwise. Alarge variety of steps in speed variation may thus be secured throughthe agency of my invention, while retaining a high degree of efficiency,together with extreme simplicity.

The cost of operation of my system is less than other systems in commonuse, on account of the absence of rheostatic controllers and the greatdifferentiation of geninitial cost of the equipment, but no repairs arenecessary in the rheostatic'controller and there is no loss of power inthe afmature circuitdue to the rheostatlc type of controller as commonlyemployed;

The weight of the installation is less on account of the fact that moreefficient design of the generator-motor system is possible and there isno rhecstatic regulator in the armature circuit (Figs. 1, 2 and t) or inthe field circuit in the structure of Fig. and in consequence the weightof the power units can be less than in' common practice, on account ofthe special, highl ehcient methods of applying the power developed. Thefield rheostat employed in connection with the structures of Figs. 1 and2 is small and inexpensive as compared with the armature rheostaticcontroller commonly m. ployed in connection with electric enerators andmotors. In the structure of Fi g. 2, however, all rheostaticcontrollers, whether of the armature or the field type, are dispensedwith and the electrical circuit controlling mechanism is reduced to thesimplest possible form, to wit, a circuit opening and reversing switch,with which no lcs's'zt'actcr obtains.

The durability of my system is greater on account of the absence of therheostatic' controller, which is one of the most troublesome links informer systems, and also on account of the uniform'and gradual manner inwhich the power may be applied, thus preventing any sudden shock or jarto the power-units themselves and to the parts of the driven structureand mechanisms.

ere, in'the appended claims, I refer to the motor field winding or fieldwindings in the independent circuit, it will be understood that I usethe word inclusively, as contemplating such field winding so connectedeither used as the sole field winding of the motor or as but part or thetotal field winding of the motor, the other part or parts beingotherwise and suitably connected in circuit.

.the' propelling means, all mounted on the conveyance and constituting aself-contained power driving unit therefor; the generator and motor'ha'ving their fields and armatures interconnected to enable thegenerator simultaneously and independently to energize its own field andthe field of the motor in advance of the energization of the motorarmature; and a switching mechanism for abruptly closing and opening themotor armature circuit from said generator independently of the motorfield to start and stop the motor.

2. A system of the class described, comprising a conveyance havingpropelling means; a prime mover, a generator drlven thereby and a motorhaving connection with ,the propelling means, all mounted on theconveyance and constitutinga self-contained power driving unit therefor;the generator and motor having their fields and armaturesinterdependently connected by two inde pendent branch circuits, onecontaining the armature of the motor and the other the motor fieldWinding; and switching mechanism for abruptly closing and opening thearmature branch circuit independently of the branch containing the saidmotor field winding, for starting and stopping the motor.

3. A system of the class described, comprising a conveyance havingpropelling means; a prime mover, a generator driven thereby and a motorhaving connection with the propelling means, all mounted on theconveyance and constituting a self-contained power driving unittherefor; the generator and motor having their fields and armaturesinterconnected by two independent branch circuits, one of which includesa motor field winding and the other the motor armature; and circuitclosing and reversing switch mechanism of the armature branch circuitfor abruptly closing and reversing the same to start, stop and reversethe motor.

4:. A system of the class described, comrisin a conve ance havin r0ellin P a:

means; a prime mover, a generator driven thereby and a motor havingconnection with the propelling means, all mounted on the conveyance andconstitutinga self-contained power driving unit therefor; the generatorand motor having their fields and armatures interconnected by twoindependent branch circuits, one of which includes the motor fieldwinding and the other the armature of the motor; and means for varyingthe output of the generator to vary the speed and torque of the motor.

5. In a system of the class described, a conveyance having propellingmeans, a prime mover, a generator driven thereby, a motor connected tothe propelling means, and two independent circuits connecting the motorto the generator armature, one of which includes a motor field windingand a generator field winding in series and the other the armature ofthe motor, and means for varying the output of the generator to vary thespeed or torque of the motor.

6. In a system of the class described, a conveyance having propellingmeans,a variable speed prime mover and a generator driven thereby, amotor connected to the propelling means, two independent branch circuitsconnecting the motor to the generator armature, one of which containsthe motor armature and the other a motor field winding and a generatorfield winding, and switching means for opening or closing the armaturecircuit and for reversing the direction of rotation of the saidarmature.

7. In a system of the class described, a conveyance having propellingmeans, a prime mover and a generator driven there by, a motor connectedto the propelling means, independent branch circuits connecting themotor to the generator armature, one containing a motor field windingand a generator field winding and the other containing a motor armature,a motor field winding and a generator field winding, means forcontrolling the output of the generator to vary the speed and torque ofthe motor, and means for controlling the starting, stopping andreversing of the motor.

8. In a system of the class described, a conveyance having propellingmeans, a prime mover and a generator driven there by, a motor connectedto the propelling means, independent branch circuits connecting themotor to the generator armature, one containing a motor field Windingand a generator field winding and the other containing the motorarmature, amotor field winding 'and a generator field winding, means forcontrolling the speed of the prime mover to vary the output of thegenerator and thereby control the speed and torque of the motor, andcircuit closing and reversing switching means associated with the motor.

9. A combined generator motor system, comprising a generator field andarmature and two independent external circuits leading from thegenerator field and armature to the motor, one of said circuitscontaining a motor armature and the other a motor field winding, meansto permit the initial energization of the field windings of thegenerator and motor, and means for subsequently abruptly closing themotor armature circuit in either direction and for opening the same forstarting, stopping or reversing the motor.

10. A system of the class described comprising a conveyance havingpropelling means, a prime-mover, a generator driven thereby and a motorhaving connection with the propelling means, all mounted on theconveyance and constituting a self-contained power producing and drivingunit therefor, two independent external circuits interconnecting thegenerator armature with the motor, one of said circuits containing themotor armature and the other a motor field winding and a generator fieldwinding, and switching meansin the motor armature circuit foropening-and closing the same tostop and start the motor.

11. A system of the class described comprising a conveyance havingpropelling means, a prime-mover, a generator driven thereby, and a motorhaving connection with the propelling means, all mounted on theconveyance and constituting a self-contained power producing and drivingunit therefor, two independent external circuits connecting thegenerator armature with the motor, one of said circuits containing themotor armature and the other a motor field winding and a generator fieldwinding, and means for opening and closing the armature circuit andreversing the direction of rotation of the motor armature.

12. A power transmission system comprising a prime mover and means forcontrolling and regulating the speed ofvthe same, a generator driven bythe prime mover, a motor, and two independent circuits connected withthe generator arma-. ture, one containing the motor armature and theother field windings of the generator and the motor.

13. A combined generator-motor system comprising a prime mover and meansfor varying the speed of the same, a generator driven by the primemover, a motor, and two independent circuits connected with thegenerator armature, one containing the motor armature and the otherfield windings of the generator and motor, and means for reversing thedirection of'rotation of the motor armature.

14:. A' combined generator-motor system comprising a prime mover andmeans for varying the speed of the same, a generator driven by the primemover, a motor, said generator and motor having compound field windings,and two independent circuits connected across the generator armature,one containing field windings of both machines and the other thearmature of the motor and field windings of both machines, and switchingmeans in the said armature circuit of the motor for opening, closing andreversing the same.

15. A combined generator-motor system comprising a variable speed primemover, a generator driven thereby, a motor, said generator and motorhaving compound field windings and commutating pole windings, and twoindependent circuits connected across the generator armature, onecircuit containing field windings of both machines and the other circuitcontaining field windings of both machines, the commutating polewindings and the motor armature, and switching means in the saidarmature circuit of the motor for opening, closing and reversing thesame.

16. A system of the class described comprising a conveyance havingpropelling means, a correlated initial source of electric energy and amotor, the said motor havlng for varying the energy impressed on saidarmature and field winding from said source, and means for opening andclosing the armature circuit independently of the field circuit to stopand start the motor.

17. A system of the class described comprising a conveyance havingpropelling means, a correlated initial source of electric energy and amotor, the motor having connection with the propelling means and allmounted on the conveyance and constituting a self-contained powerproducing and driving unittherefor, the motor having its armature andfield winding independently excited from said initial source of current,said armature and field winding being in independent branch circuits,the field branch circuit of the motor containing also a field winding ofthe initial current source, means for varying the energy impressed onthe said armature and field winding, and means for opening and closingand reversing the armature circuit independentlyv of .and withoutaffecting the field circuit to stop, start and reverse the motor.

18. A system of'the class described, comprising a conveyance havingpropelling means, a correlated initial source of electrical energy and amotor, the said motor having connection with the propelling means andall mounted on the conveyance and constituting a self-contained powerproducing and driving unit therefor, the motor having a field Windingconnected in a closed circuit with the said source of energy whereby thesaid field winding is continuously excit d during the generation of theenergy by sa (1 source, said closed circuit including a field winding of.said initial current source, the armature of the motor being connectedin a circuit from said source which is independent of the said fieldcircuit, means for varying the output of the source of energy,

and switching means for opening and closall mounted on the conveyanceand constituting a self-contained power producing and driving unittherefor, the motor having a field Winding connected to said source ofenergy and continuously excited thereby, the said connection containinga field winding of the initial current source, a circuit independent ofthe field circuit and including the armature of the motor, means forvarying the output of said source of energy to vary the excitation ofthe said armature and field, and switching means to open and close andreverse the armature circuit without affecting the field circuit tostop, start and reverse the motor.

20. A system of the class described, comprising a conveyance havingpropelling means, a correlated initlal source of electrical energy and amotor, the motor having connection with the propelling means and allmounted on the conveyance and constituting a self-contained powerproducing and driving unit therefor, a pair of independent branchcircuits extending from said source of electricity to said motor, themotor armature being in one of said branches and the motor field windingand a generator field winding in the other of said branches, means forvarying the voltage of current from said source that is impressed uponsaid circuits to thereby vary the speed or torque of said motor, andswitching means for opening and closing the branch circuit containingthe armature without deenergr zation of the motor field winding to startand stop the motor.

21. A system of the class described, comprising a conveyance havingpropelling means, a correlated initial source of electrical energy and amotor, the motor having connection with the'propelling means and allmounted on the conveyance and constituting a self-contained powerproducing and driving unit therefor, a pair of independent branchcircuits extending from said source, the armature of the motor being inone of said branches and a field winding of said motor and of saidgenerator in the other of said branches, means for varying the voltageof current from said source to vary the speed or torque of said motor,and switching means for opening and closing the armature circuit and forreversing the direction of current therethrough to start, stop andreverse the motor.

22. The herein described method of furnishing power for propulsionpurposes which consists in rotating an electromagnetic member in a fieldof force to produce an electric current, delivering a divisible part ofsaid current to produce said field of force and directly to energize arelatively stationary electromagnetic member, delivering a divisiblepart thereof directly to energize a relatively rotary electromagneticmember in the magnetic field of said stationary member, and varying thevoltage of the current generated in said first-mentioned electromagneticmember to thereby vary the speed and torque of said last-mentionedrotary member.

23. The herein described method of operating a power driving unit forconveyances, consisting of prime-mover, generator and motor, whichconsists in mechanically operating the generator from the primemover togenerate an electric current, delivering a part of said current toconstantly energize the relatively stationary electromagnetic members ofboth generator and motor, delivering a part of said current to abruptlyenergize and cause the rotation in the desired direction of the rotaryelectrodynamic member of the motor, and controlling at will the speed ofthe prime-moverv to control the speed and torque of the motor.

24:. A system of the class described comprising a conveyance havingpropelling means; a prime-mover, a generator driven thereby and a motorhaving connection with the propelling means, all mounted on theconveyance and constituting a self-contained power driving unittherefor; the generator and motor having their fields and armaturesinterconnected to enable the generator simultaneously and independentlyto energize its own field and the field of the motor in advance of theenergization of the motor armature; and a switching mechanism forclosing and opening the motor armature circuit from said generatorindependently of the motor field to start and stop the motor.

25. A system of the class described, comprising a conveyance havingpropelling means; a prime-mover, a generator driven thereby and a motorhaving connection with the propelling means, all mounted on theconveyance and constituting a self-contained power driving unittherefor; the generator and motor having their fields and armaturesinterconnected to enable the generator simultaneously and independentlyto energize its own field and the field of the motor in advance of theenergization of the motor armature; and circuit closing and reversingswitch mechanism in the armature circuit of the motor for closing andreversing the same to start, stop and reverse the motor.

26. A system of the class described comprising a conveyance havingpropelling means; a prime-mover, a generator driven thereby and a motorhaving connection with the propelling means, all mounted on theconveyance and constituting a self-contained power driving unittherefor; the generator and motor having the fields and armaturesinterconnected to enable the generator to energize its own field and thefield and armature of the motor; and means for varying the output of thegenerator to vary the speed and torque of the motor.

27 A combined generator motor system comprising a generator field andarmature and two independent external circuits leading from thegenerator field and armatureto the motor, one of said circuitscontaining a motor armature and the other a motor field winding, meansto Permit the initial energization of the field windings of thegeneradirection and for opening the same for' starting, stopping orreversing the motor.

In witness whereof, I have hereunto subscribed my name 1n the presenceof two witnesses.

- JOHN R. MARKLE.

Witnesses:

MABEL Rnrnonns, W. PERRY HALM.

